Unmarked bugelspanner (attrib. J O Ahlstedt, Stockholm)

Unmarked bugelspanner (attrib. J O Ahlstedt, Stockholm) 

With thanks to Thoralf for these pics.

This rifle is similar to this one:

https://forum.vintageairgunsgallery.com/spring-piston-crank-wound-airguns/ahstedt-j-o-stockholm/#post-4658

Thoralf says: "No markings anywhere and with a brass barrel insert.  The other one has a steel barrel. Caliber is 6,5mm too." 

This one was auctioned, also attributed to Ahlstedt:

and this one: